Highly‐Entangled Hydrogel Electrolyte for Fast Charging/Discharging Properties in Aqueous Zinc Ion Batteries

Abstract Aqueous zinc ion batteries coupling with conventional hydrogel electrolyte have the advantages of high safety, low cost, and simple manufacturing process while they are difficult for fast charging/discharging application scenarios due to the sluggish kinetics. Herein, a new strategy is developed for synthesizing a highly‐entangled polyacrylamide (HE‐PAM) hydrogel electrolyte to dramatically enhance the ion transportation and mechanical stability. The developed hydrogel electrolyte has lower ionic resistance and a strong elastic modulus. After being assembled into Zn/MnO 2 batteries, the HE‐PAM hydrogel electrolyte exhibits excellent cycling stability and high‐rate capability under high current densities. Specifically, the Zn//HE‐PAM//MnO 2 battery can resist the highest current of 35 A g −1 , which outperforms previously reported works. Moreover, the HE‐PAM hydrogel electrolyte can also support the fast charging/discharging in proton ion batteries with a high capacity retention rate of 50% under 50 A g −1 . This progress on hydrogel electrolytes can boost the development of quasi‐solid‐state batteries in the fast charging/discharging aspect.